Cooking Bags

ABSTRACT

A packaging suitable for use in or on a heating appliance, comprising a bag in which, in use, is sealed an article for heating. The bag has an aperture formed therein over which is sealed a film of material which forms a window in the bag, wherein the seal between said film and the material of the bag is sensitive to temperature and/or pressure such that the window at least partially detaches automatically from the bag upon the temperature and/or pressure within the bag reaching a predefined level so as to vent the atmosphere within the bag.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a national stage filing of International Patent App. No. PCT/GB2005/004321, filed on Nov. 9, 2005, which claims priority from GB Patent App. No. 0428229.9 filed on Dec. 22, 2004, and claims priority from GB Patent App. No. 0522886.1 filed on Nov. 9, 2005, herein incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to sealed bags in which food stuffs can be cooked.

2. State of the Art

In recent times, there has been a general move towards providing pre-packaged food stuffs in packaging which can be put straight into a cooking appliance such as an oven, the food contained within the packaging then being cooked whilst still contained within the packaging. This has the advantage that the packaging can contain and, if appropriate control the cooking environment to a degree, for example by controlling the pressure within the packaging, so improve the cooking operation. Different food types may also be cooked in the same oven without being exposed to each other, which the case of particularly aromatic foods, can result in a detrimental effect on the taste of the food. Furthermore, the cooking by-productions such as juices and the like are retained within the packaging and can easily be disposed of following removal of the packaging from the oven, thereby providing a much cleaner cooking experience.

These systems have the drawback, however, that once cooking is finished, the packaging must be removed from the cooking appliance and then opened to enable the contents to be removed for consumption. The packaging is normally very hot when it is so removed from the appliance and there is hence a high risk of the user burning themselves during this operation.

SUMMARY OF THE INVENTION

According to the present invention there is provided packaging suitable for use in or on a heating appliance, comprising a bag in which, in use, is sealed an article for heating, the bag having an aperture formed therein over which is sealed a film of material which forms a window in the bag, wherein the seal between said film and the material of the bag is sensitive to temperature and/or pressure such that the window at least partially detaches automatically from the bag upon the temperature and/or pressure within the bag reaching a predefined level so as to vent the atmosphere within the bag.

A packaging in accordance with the invention has the advantage that the food stuffs can be packed within the bag for compact storage and, upon heating, the increase in pressure will cause the packaging to expand to form a pillow before the window vents the internal atmosphere. The aperture within the bag can then be used to remove the food from the packaging once it is cooked using suitable tongs or the like without the user having to handle the packaging itself, the film then being easily removable by the user fully to expose the aperture. In this way, the problems of the prior art system are overcome whilst the advantages such as containing the cooking by-products are maintained.

Preferably, the bag is formed of a material which is stiff enough to maintain the pillowed shape of the bag once the internal pressure is released upon detachment of the window. In this way, the bag can advantageously be used as a container to serve the food through the window.

Advantageously, the film window is sealed to the foil with a seal that has a rupture strength lower than that of the bag such that, in use, the bag allows any steam build up to vent without rupturing the bag, thus removing any need for the customer to pierce the bag.

Preferably, the strength of the seal is furthermore such that, in use, the window is user detachable at any time. In this way, the film can be removed early on in the cooking process for a drier, more roasted result, whilst the film can be left in place longer for a more steamed, succulent result.

Preferably, the bag is formed of an aluminium foil material, in particular of gauge between substantially 25 and 500 microns, but preferably of gauge between substantially 25 and 100 microns, which has advantageously high temperature resistance suitable for withstanding the high temperatures of grilling and oven cooking. Desirably, the aperture is formed in one side panel of the bag which, in use, may be positioned upward facing in a cooking appliance. The film is preferably formed of a polyester or polyester polythene material and may be formed as a panel which is slightly larger than the aperture in the bag, the overlap with the bag providing the seal between the film and the bag, or, alternatively, may extend across the whole side panel of the bag in which the aperture is formed.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be well understood, an embodiment of the invention is shown in the accompanying drawings, in which:

FIG. 1 is a perspective view of a packaging according to the invention in an open configuration; and

FIG. 2 is a perspective view of a packaging of FIG. 1 in a closed configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment as shown in FIGS. 1 and 2, the packaging of the invention is realized by a bag 1 formed of a film 2. The film 2 may be transparent so as to enable view of the food stuff whilst the packaging is still sealed. Advantageously, the film 2 is furthermore anti-fog coated to ensure that the food stuff can be seen at all times, particularly when, in use, the bag 1 is taken out of a chiller and on to a hot grill.

Some food products may require breathable properties for which a suitable film solution can be produced. The gas transmission rates can then be adjusted, preferably via micro-perforations in the film 1, to match the respiration rate of the food stuff to be stored therein so as to maximise the shelf life of the product.

The packaging may have food stuffs pre-packaged therein, but, in one embodiment is provided with a user sealable opening 5 by means of which user prepared products can be inserted into the bag and the bag then sealed for cooking the produce in the manner described above. The opening 5, for example, may be provided with an adhesive strip 6 of a strength which has a greater resistance to pressure than the seal 3 between the window 4 and the bag 1. In particular, the adhesive 6 may be provided on a lip 7 which is folded over a number of times before adhering to the bag 1 so as to ensure a good seal. Advantageously, the sealable opening 5 is created with adhesive 5 on the outside of the bag only such that no adhesive can, in use, migrate into the food stuff within the bag 1 when very high temperatures are reached. Preferably, however, the opening 5 is sealable, either mechanically or by hand, without adhesive 5. In particular, the lip 7 of the opening is desirably folded over a number of times before being crushed together so as to ensure a good seal. Alternatively, though, where the bag 1 is formed of a weldable material, the opening 5 is sealable with a permanent weld seal once the bag 1 has been filled with a food product. In particular, ultrasonic welding is desirably used to create the weld seal.

The packaging is suitable for a wide range of cooking appliances but is particularly advantageous for use on a barbeque or the like, the bag 1 with a pre-prepared food product, in possibly a raw, partially or fully cooked state, being placed directly onto the barbeque with the window 4 facing upwards so as to prevent escape of cooking by-products or the like from the bag 1. Upon the bag 1 expanding into a pillow shape, the material of the bag 1 is preferably stiff enough to support itself in its expanded position once the film 2 has released to vent the bag 1 and hence relieve the internal pressure. 

1. An article for preparing foodstuff comprising: a bag for holding foodstuff, the bag realized from a material that maintains structural integrity under high temperature direct heat, the bag having an aperture formed therein, a film that covers the aperture, a seal disposed between the film and the bag outside the aperture, wherein the seal automatically breaks upon at least one of temperature and pressure within the bag reaching a predefined temperature and a predefined pressure so as to vent the interior of the bag to atmosphere.
 2. An article according to claim 1, wherein: the material of the bag is stiff enough to support its own weight and to maintain an inflated shape when the seal automatically breaks in use.
 3. An article according to claim 1, wherein: the material of the bag comprises aluminium foil.
 4. An article according to claim 3, wherein: the aluminium foil is of gauge between substantially 25 and 500 microns.
 5. An article according to claim 1, wherein: the aperture is formed in one side panel of the bag.
 6. An article according to claim 1, wherein: the film comprises one of polyester and polyester polythene.
 7. An article according to claim 1, wherein: the film has a border running proximate to the aperture.
 8. An article according to claim 7, wherein: the film extends across the whole side panel of the bag in which the aperture is formed.
 9. An article according to claim 1, wherein: the film is transparent.
 10. An article according to claim 1, wherein: the film has means for gas transmission therethrough at a gas transmission rate that corresponds to the respiration rate of foodstuff stored in the bag.
 11. An article according to claim 1, wherein: the bag has a user-sealable opening for removably inserting foodstuff into the bag.
 12. An article according to claim 11, wherein: the opening is provided with an adhesive strip of a strength which has greater resistance to pressure than the seal.
 13. An article according to claim 12, wherein: the adhesive strip is provided on a lip which, in use, is folded over a number of times before adhering to the bag.
 14. An article according to claim 1, wherein: the bag holds foodstuff pre-packaged therein.
 15. (canceled)
 16. An article according to claim 1, wherein: the high temperature direct heat is provided by a barbecue grill.
 17. An article according to claim 1, wherein: the material of the bag comprises a metal film.
 18. A method for preparing foodstuff comprising: providing a sealed bag whose interior space holds foodstuff, the bag realized from a material that maintains structural integrity under high temperature direct heat, the bag having an aperture formed therein, a film that covers the aperture, a seal disposed between the film and the bag outside the aperture, wherein the seal automatically breaks upon at least one of temperature and pressure within the interior space of the bag reaching a predefined temperature and a predefined pressure; and applying high temperature direct heat to the bag such that the seal automatically breaks and vents the interior space of the bag to atmosphere.
 19. A method according to claim 18, wherein: the step of applying the high temperature direct heat is carried out on a barbecue grill.
 20. A method according to claim 18, wherein: the material of the bag comprises a metal film. 